Most modern livestock handling facilities include a system by which waste liquids and solids are collected. A popular method of collecting waste and cleaning livestock holding areas such as a barn floor involves flushing the floor with water under pressure. The resulting slurry of water and waste is then directed to a holding tank or lagoon to await further processing. Removal of waste by this method is satisfactory. But equipment for separating the solids and liquids from the resulting slurry has not been adequately developed until the advent of the present invention.
The problem is recognized from the need to effect nearly complete separation of solids from liquids in situations where both liquids and solids are to be reused. The solids should be as dry as possible for future use as bedding or feed supplements. Known existing and past forms of separators will not separate the high percentage of liquids necessary to leave adequately dry solids, especially if the solids are to be recycled as a percentage of livestock feed.
An attempted solution to the separation problem is recognized in the Swanson et al U.S. Pat. No. 3,971,720. The Swanson patent discloses a method and apparatus for processing cattle excrement. The apparatus includes a series of press rolls for successively compacting the solids from a slurry to separate the liquids. The slurry is first received between a first pair of the rollers. One of the rollers is driven to move the liquids and solids between it and the remaining roller. The two rollers are sprung toward one another to press an initial amount of the liquid from the slurry. The partially separated solids and liquids contained therein are then dropped to another pair of rollers which perform the same function again. This process is repeated until the solids become sufficiently dry for reuse.
U.S. Pat. No. 3,950,562 to Senior discloses an apparatus for removing ash and inorganic compounds from cattle manure. This device makes use of an inclined conveyor having a series of longitudinally spaced baffles on its working flight that are powered to move toward the upper end of the conveyor. A slurry is discharged onto the working flight of the conveyor so the liquids will cascade over the baffles while the solids are carried upwardly to a discharge end of the conveyor.
U.S. Pat. No. 4,348,280 to Schipper discloses a device for removing liquids from solids. Press rolls are oriented along a flexible conveyor arrangement. A layer of the moist mixture can be progressively pressed between rotating drums and the operating surface of the conveyor belt.
U.S. Pat. No. 3,959,135 to Shattock discloses an apparatus somewhat similar to the Schipper device discussed above with the exception that the conveyor is driven along a stright longitudinal path between vertically opposed press rolls where in Schipper, the conveyor path is diverted to engage in greater circumferential area of contact between the waste material and drum surface.
U.S. Pat. No. 4,186,098 to Morris discloses an arrangement by which sludge is dewatered. A series of the opposing press rolls are situated along a perforated conveyor carrying sludge. The rolls are particularly shaped to maintain the liquid of the slurry along the center of the conveyor by forming the working flight of the conveyor into a trough configuration.
Even with provision of the above-described apparatus, there remains a need for a manure separating apparatus that will operate to efficiently and effectively reduce the moisture content of resulting dried solids in an efficient and economic manner.